When using a computer system having a modern graphical operating system, it is often desirable to view a preview of a document. A document preview is a read-only rendering of a document that mimics what a user would have seen if the document was opened with an application program associated with the document. Some application programs allow a user to view a static image of a document, but the static image is not a true preview that the user can page through or navigate. Other programs require a user to launch an application program associated with the document to view its contents. For instance, within an electronic mail (“e-mail”) client application program, it is sometimes desirable to view a preview of one or more documents attached to an e-mail message. Current e-mail application programs, however, require a user to launch the application associated with the attached document to view the document. This process can be time consuming and frustrating for a user.
It is also desirable to view a document preview within various contexts. For instance, it may be desirable to view a document preview from within the context of an application program, such as the e-mail client application program described above. It also may be desirable to view a document preview from within the context of an operating system program, such as a graphical desktop shell. For instance, when a user utilizes the shell to navigate to a folder containing documents, it may be desirable for the user to quickly view a preview of the documents without the need to launch an associated application program. Similarly, it may be desirable to quickly view a document preview in the context of a dialog box utilized for opening files. In this manner, a user could view a document preview and quickly examine the contents of the document without the need to open an application program associated with the document. However, in order to preview documents utilizing current systems, each application program and operating system must implement their own code for previewing documents.
It may also be desirable to provide a facility for quickly previewing documents within various contexts without affecting the responsiveness of the computer system. Moreover, any errors encountered when previewing a document should not impact the performance or stability of a host operating system or application. It is with respect to these considerations and others that the various embodiments of the present invention have been made.